JP7147976B2 - Vacuum pump and magnetic bearing integrated motor - Google Patents

Description

The present invention relates to a vacuum pump and magnetic bearing integrated motor.

Conventionally, vacuum pumps and magnetic bearing integrated motors are known. Such a vacuum pump is disclosed, for example, in Japanese Patent No. 3854998.

The above Japanese Patent No. 3854998 discloses a bearingless motor used in a vacuum pump such as a turbomolecular pump. The bearingless motor disclosed in Japanese Patent No. 3854998 includes a rotor, a stator, and permanent magnets. In the bearingless motor disclosed in Japanese Patent No. 3854998, the permanent magnets are arranged such that the polarities of the magnetic poles are opposite to each other in the radial direction of the rotor. In addition, the bearingless motor disclosed in Japanese Patent No. 3854998 is designed such that the supporting magnetic flux generated by the current flowing in the supporting windings provided in the stator penetrates the salient poles arranged between the permanent magnets. It is configured. With this configuration, the stator generates a supporting force for magnetically supporting the rotor without contact.

In addition, the bearingless motor disclosed in Japanese Patent No. 3854998 has a fixing member provided on the outer periphery of the permanent magnet in order to prevent the permanent magnet from scattering due to the centrifugal force generated by the rotation of the rotor. It is Although not disclosed in Japanese Patent No. 3854998, the fixed member for preventing scattering of the permanent magnets is made of, for example, stainless steel so as not to be damaged by the pressure applied during assembly of the rotor. It is thought that there are

Japanese Patent No. 3854998

However, for example, when the fixed member having an annular shape for preventing scattering of the permanent magnet is made of stainless steel, the magnetic flux for generating the supporting force for the magnetic support causes eddy currents in the fixed member. occurs. If an eddy current occurs in the fixed member, power consumption becomes excessively large, resulting in a loss of power for driving the motor and power for generating a supporting force for magnetically supporting the motor. Therefore, it is conceivable to suppress the occurrence of eddy current in the fixing member by forming the fixing member from a non-conductive material such as resin. However, if the fixing member is made of resin or the like, there is a problem that the fixing member may be damaged by the pressure during assembly of the rotor.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems described above, and an object of the present invention is to prevent the fixing member from being damaged during assembly, and to prevent the fixing member from being damaged. An object of the present invention is to provide a vacuum pump and magnetic bearing integrated motor capable of reducing loss due to eddy currents.

In order to achieve the above object, a vacuum pump according to a first aspect of the present invention includes a rotor including a rotating shaft having an axial direction, rotor blades provided on the rotating shaft, a rotational force that rotationally drives the rotor, and and a magnetic bearing integrated stator including coils for applying a bearing force to magnetically support the rotor, the rotor being provided on the outer periphery of the pair of spacer members and the rotating shaft, which is applied in the axial direction during assembly. A support member for receiving pressure via a pair of spacer members; a permanent magnet provided so as to surround the outer periphery of the support member; a non-conductive protective ring having a closed toroidal shape, wherein the mechanical strength in the axial direction of the rotating shaft of the supporting member is greater than the mechanical strength in the axial direction of the protective ring. It should be noted that the non-conductive protective ring includes an insulator or a semiconductor. Further, the mechanical strength in the axial direction is strength (rigidity) against compressive load in the axial direction.

A magnetic bearing-integrated motor according to a second aspect of the present invention includes a rotor including a rotating shaft having an axial direction, and a coil that imparts a rotational force that rotationally drives the rotor and a bearing force that magnetically supports the rotor. a stator integrated with a magnetic bearing, wherein the rotor includes a pair of spacer members and a support member provided on the outer periphery of the rotating shaft for receiving pressure applied in the axial direction during assembly via the pair of spacer members. a permanent magnet provided so as to surround the outer periphery of the support member; and a non-conductive protective ring having an annular shape provided axially without contact with the pair of spacer members on the outer periphery of the permanent magnet; and the mechanical strength of the supporting member in the axial direction of the rotating shaft is greater than the mechanical strength of the protective ring in the axial direction.

In the first aspect of the present invention, as described above, a pair of spacer members, a support member for receiving pressure applied in the axial direction during assembly through the pair of spacer members, and and a non-conductive protection ring having an annular shape provided on the outer periphery of the permanent magnet, wherein the mechanical strength in the axial direction of the rotating shaft of the support member is greater than the axial direction of the protection ring greater than the mechanical strength in By providing the support member, it is possible to prevent the protective ring from being damaged during assembly. Moreover, by providing the non-conductive protective ring, it is possible to reduce loss due to eddy currents occurring in the protective ring. As a result, it is possible to suppress damage to the protective ring during assembly, and to reduce loss due to eddy currents occurring in the protective ring.

Further, in the second aspect of the present invention, by configuring as described above, it is possible to suppress damage to the protective ring during assembly, as in the case of the vacuum pump in the first aspect, and It is possible to provide a magnetic bearing integrated motor capable of reducing loss due to eddy currents occurring in the protective ring.

1 is a schematic cross-sectional view showing the overall configuration of a vacuum pump; FIG. FIG. 4 is a schematic diagram showing the arrangement of a rotating body, a magnetic bearing unit, and a motor unit; FIG. 3 is a block diagram for explaining a controllable configuration of a vacuum pump; FIG. 4 is a schematic cross-sectional view of the magnetic bearing unit and the motor unit as seen from the radial direction; FIG. 3 is a schematic cross-sectional view of the motor unit viewed from the axial direction; It is a typical sectional view which looked at the motor rotor from the axial direction. It is a typical sectional view which looked at the motor rotor from the radial direction. It is a typical sectional view which looked at the motor rotor by the 1st modification from the radial direction. It is a typical sectional view which looked at the motor rotor by the 2nd modification from the radial direction. It is a typical sectional view which looked at the motor rotor by the 3rd modification from the radial direction. It is a typical sectional view which looked at the motor rotor by the 4th modification from the radial direction. FIG. 11 is a schematic cross-sectional view of a motor rotor according to a fifth modification as seen from the axial direction;

Embodiments embodying the present invention will be described below with reference to the drawings.

A configuration of a magnetic bearing integrated motor 22 according to an embodiment of the present invention and a configuration of a vacuum pump 100 including the magnetic bearing integrated motor 22 will be described with reference to FIGS. 1 to 7. FIG.

(Structure of vacuum pump)
As shown in FIG. 1, the vacuum pump 100 is a pump for discharging gas from the container and evacuating (decompressing) the container. Note that the vacuum is a state of pressure lower than the atmospheric pressure around the vacuum pump 100 .

The vacuum pump 100 comprises at least one inlet 1 , at least one outlet 2 and at least one pump section 3 . The vacuum pump 100 sucks gas into the pump portion 3 through the suction port 1 and discharges the sucked gas through the exhaust port 2 by the operation of the pump portion 3 . The vacuum pump 100 comprises a housing 4 containing the pump section 3 . In the example of FIG. 1, the housing 4 is formed with one intake port 1 and accommodates one pump section 3 . An exhaust pipe 2 a having an exhaust port 2 is connected to the housing 4 . The exhaust port 2 communicates with the intake port 1 via an exhaust pipe 2 a and a pump portion 3 .

In addition, in the example of FIG. 1, the vacuum pump 100 is provided with a control unit 5 for controlling the operation of the pump section 3 . A control unit 5 is attached to the bottom of the housing 4 . The control unit 5 may be provided separately from the vacuum pump 100 and may be connected to the vacuum pump 100 by wire or wirelessly so as to be communicable.

(pump section)
The pump section 3 includes a rotating body 10 and a rotating mechanism 20 . Rotating body 10 and rotating mechanism 20 are accommodated in housing 4 . A gas attraction force is generated between the rotating body 10 and the housing 4 by rotating the rotating body 10 by the rotating mechanism 20 .

In the configuration example of FIG. 1, the pump section 3 includes a first pump structure 3a and a second pump structure 3b. In the example of FIG. 1, the vacuum pump 100 is a composite vacuum pump in which a first pump structure 3a and a second pump structure 3b are connected in series. The gas taken into the pump section 3 through the intake port 1 passes through the first pump structure 3 a and the second pump structure 3 b in order and is discharged from the exhaust port 2 .

The rotary body 10 includes a rotary shaft 11 , a blade support portion 12 and rotary blades 13 . The rotating body 10 is provided so that the rotating shaft 11, the blade supporting portion 12, and the rotating blades 13 rotate integrally. The first pump structure 3a constitutes a turbomolecular pump with the rotor blades 13 of the rotating body 10 and the fixed blades 71 of the housing 4 . The rotating body 10 includes a cylindrical portion 14 extending from the wing supporting portion 12 toward the other end 11b of the rotating shaft 11 and forming a second pump structure 3b together with the housing 4 . The rotating body 10 is provided with a rotor blade 13 forming the first pump structure 3a and a cylindrical portion 14 forming the second pump structure 3b so as to rotate integrally. The second pump structure 3b constitutes a molecular drag pump by the cylindrical portion 14 of the rotor 10, which will be described later, and the pump stator 73 of the housing 4. As shown in FIG.

Hereinafter, the direction in which the central axis of the rotating shaft 11 extends will be referred to as an axial direction or a thrust direction. The radial direction of the rotating shaft 11 is simply referred to as the radial direction. In each figure, the axial direction is the Z direction, the Z1 direction of the Z directions is called the one end 11a side, and the Z2 direction is called the other end 11b side.

As shown in FIG. 1, the rotating mechanism 20 includes a magnetic bearing integrated motor 22 that drives the rotating body 10 to rotate and supports the rotating body 10 by magnetism. The rotating mechanism 20 is provided so as to surround the rotating shaft 11 around the rotating shaft 11 .

The magnetic bearing integrated motor 22 is composed of a motor stator 22a (see FIG. 4) and a motor rotor 22b (see FIG. 4). The motor rotor 22b includes a rotating shaft 11 having an axial direction. The motor stator 22a is configured to apply a rotational force to rotationally drive the motor rotor 22b and a bearing force to magnetically support the motor rotor 22b. The motor stator 22a and the motor rotor 22b are examples of a "magnetic bearing integrated stator" and a "rotor", respectively.

The magnetic bearings are 5-axis magnetic bearings including two sets of radial magnetic bearings and one set of thrust magnetic bearings. The 5-axis means that position control and attitude control are possible in 5 directions of 3 translational directions and 2 tilting directions of the rotating body 10 .

That is, the rotating mechanism 20 includes a first radial magnetic bearing 40 provided around the rotating shaft 11 and a magnetic bearing integrated motor 22 functioning as a second radial magnetic bearing. The rotating mechanism 20 includes a thrust magnetic bearing 60 provided around the rotating shaft 11. The magnetic bearing enables the rotating body 10 to rotate without contact with the rotating body 10 by magnetically levitating the rotating body 10. To support.

A set of radial magnetic bearings enables position control (two axes) in two radial directions (X direction and Y direction) perpendicular to each other. By using two sets of radial magnetic bearings arranged side by side in the axial direction, it is possible to control the attitude of the tilt around the X direction and around the Y direction. The thrust magnetic bearing enables position control (one axis) in the thrust direction (Z direction).

In this embodiment, the rotation mechanism 20 includes at least a magnetic bearing unit 21 and a magnetic bearing integrated motor 22 . The magnetic bearing unit 21 includes at least first radial magnetic bearings 40 . In this embodiment, in the configuration example of FIG. 1 , the magnetic bearing unit 21 is a single unit that integrally includes the first radial magnetic bearing 40 and the thrust magnetic bearing 60 . The magnetic bearing integrated motor 22 is a unit that operates both as a motor that rotates the rotating shaft 11 and as a second radial magnetic bearing that magnetically supports the rotating shaft 11 . In this way, the structure that operates as both the motor that rotates the rotating shaft 11 and the second radial magnetic bearing eliminates the need for a set of radial magnetic bearings that are normally provided separately from the motor. , or self-bearing motors. That is, the “magnetic bearing integrated motor” is a motor that rotates the rotating shaft 11 at the same position in the axial direction and functions as a magnetic bearing for the rotating shaft 11 . Detailed configurations of the magnetic bearing unit 21 and the magnetic bearing integrated motor 22 will be described later.

The housing 4 includes a base portion 4a and a case portion 4b. A rotating mechanism 20 is provided on the base portion 4a, and a rotating shaft 11 of the rotating body 10 is inserted therein. An exhaust pipe 2a is connected to the base portion 4a. The case portion 4b is attached to the upper surface of the base portion 4a. The case portion 4b is formed in a cylindrical shape so as to surround the rotating body 10 installed on the base portion 4a, and has an intake port 1 formed on its upper surface.

The vacuum pump 100 also has a plurality of mechanical bearings 6, a plurality of displacement sensors 7a, 7b, 7c, 7d and 7e, and a rotation sensor 8. A plurality of mechanical bearings 6 are provided in the vicinity of one end 11a and the vicinity of the other end 11b of the rotary shaft 11 in the base portion 4a. The mechanical bearing 6 can contact the rotating shaft 11 and support the rotating shaft 11 in the radial direction and the thrust direction. The mechanical bearing 6 is a touchdown bearing that supports the rotating body 10 instead of the magnetic bearing when the magnetic bearing is not operating (when magnetic levitation is not occurring) or when disturbance occurs. During operation of the magnetic bearing, the mechanical bearing 6 and the rotating shaft 11 (rotating body 10) are out of contact.

As shown in FIG. 3, the displacement sensors 7a to 7d respectively detect the displacement of the rotating shaft 11 in the radial direction (X1 direction, Y1 direction, X2 direction, Y2 direction). The displacement sensor 7e detects displacement of the rotating shaft 11 in the thrust direction (Z direction). A rotation sensor 8 detects the rotation angle of the rotation shaft 11 .

The control unit 5 includes a control section 81 , a power supply section 82 , a unit driving section 83 and a sensor circuit section 84 .

The power supply section 82 acquires power from an external power supply and supplies power to the control section 81 , the unit drive section 83 and the sensor circuit section 84 . The power supply unit 82 performs power conversion to convert AC power from the outside into DC power.

The unit drive section 83 controls the supply of drive current to the rotation mechanism 20 based on the control signal from the control section 81 . By current control in the unit drive section 83, the magnetic bearing integrated motor 22 of the rotating mechanism 20 generates driving force (torque) in the rotational direction, and the magnetic bearings generate supporting forces in each direction. Unit driving section 83 includes inverters 85 a and 85 b for controlling current supply to magnetic bearing unit 21 . Unit driving section 83 includes inverters 85 c and 85 d for controlling current supply to magnetic bearing integrated motor 22 . Inverters 85a-85d each include a plurality of switching elements.

The sensor circuit section 84 includes the displacement sensors 7a to 7e and the rotation sensor 8, and includes a circuit for performing conversion processing for inputting each sensor signal to the control section 81, and the like. Sensor signals of the displacement sensors 7 a to 7 e and the rotation sensor 8 are input to the control section 81 from the sensor circuit section 84 .

The control unit 81 is configured by a computer including a processor such as a CPU (Central Processing Unit) or FPGA (Field Programmable Gate Array), and volatile and/or nonvolatile memory.

The control section 81 controls the operation of the rotation mechanism 20 via the unit driving section 83 . The control unit 81 acquires sensor signals in each direction from the sensor circuit unit 84, and based on the acquired sensor signals, performs control for on-off controlling a plurality of switching elements provided in the inverters 85a, 85b, and 85d. Output a signal. Thereby, the control unit 81 controls each magnetic bearing so that the rotating body 10 does not come into contact with any fixed element of the vacuum pump 100 during operation of the vacuum pump 100 .

Based on the sensor signal from the rotation sensor 8, the control unit 81 outputs a control signal for on/off controlling the plurality of switching elements provided in the inverter 85c. Thereby, the controller 81 controls the magnetic bearing integrated motor 22 based on the rotational position of the rotating body 10 .

(Structure of rotating body)
As shown in FIG. 2, the rotating shaft 11 is a cylindrical member having one end 11a and the other end 11b. In the example of FIG. 1, the one end 11a is the upper end of the rotating shaft 11, and the other end 11b is the lower end of the rotating shaft 11. As shown in FIG. The rotary shaft 11 is bearing-supported by a rotary mechanism 20 so as to be rotatable around the central axis. Further, the rotating shaft 11 is driven to rotate about the central axis by a rotating mechanism 20 . Although FIG. 1 shows an example of a vertical vacuum pump 100 in which the rotating shaft 11 extends along the vertical direction (vertical direction), the direction of the rotating shaft 11 is not particularly limited. The rotating shaft 11 may be arranged horizontally or obliquely.

The blade supporting portion 12 is a portion of the rotating body 10 that mechanically connects the rotating blade 13 and the rotating shaft 11 . The wing support portion 12 is connected to the one end 11a side of the rotating shaft 11 . The wing support portion 12 extends toward the other end 11b side of the rotating shaft 11 so that its inner diameter increases. That is, the blade support portion 12 is generally formed in a conical shape directed toward the one end 11 a of the rotating shaft 11 . The blade support portion 12 has a tapered portion 12a that is inclined from the other end 11b side of the rotating shaft 11 toward the one end 11a side. The wing support portion 12 has a flange portion 12b radially extending from one end 11a of the rotary shaft 11. As shown in FIG. The tapered portion 12a is mechanically connected to the outer peripheral edge of the flange portion 12b.

The rotor 10 has a plurality of rotor blades 13 . The rotor blades 13 are provided on the outer peripheral surface of the blade support portion 12 . The rotor blades 13 radially extend from the outer peripheral surface of the blade support portion 12 to the vicinity of the inner peripheral surface of the housing 4 .

The impeller 13 forms the first pump structure 3a with the housing 4, as described above. The plurality of rotor blades 13 are provided in multiple stages at intervals in the axial direction. The plurality of rotor blades 13 are arranged along the outer peripheral surface of the tapered portion 12a and the outer peripheral surface of the flange portion 12b.

Further, as shown in FIG. 1 , a plurality of fixed wings 71 are provided on the inner peripheral surface of the housing 4 . Each fixed wing 71 extends radially inward (rotating shaft 11 side) from the inner peripheral surface of the housing 4 . The plurality of fixed blades 71 and the plurality of rotor blades 13 are arranged alternately in the axial direction one by one. Each fixed wing 71 is placed on the base portion 4a via spacer rings 72 that are stacked in the axial direction. Each stationary blade 71 is positioned by sandwiching the laminated spacer ring 72 between the base portion 4a and the case portion 4b. Thus, the pump section 3 includes a first pump structure 3 a configured by the rotor blades 13 (moving blades) of the rotating body 10 and the stationary blades 71 (stationary blades) of the housing 4 .

The cylindrical portion 14 has a cylindrical shape coaxial with the rotating shaft 11 . The cylindrical portion 14 has a first end portion 14 a connected to the blade support portion 12 and a second end portion 14 b on the side opposite to the blade support portion 12 in the axial direction of the rotating shaft 11 . The cylindrical portion 14 extends linearly along the axial direction from a first end portion 14a connected to the tapered portion 12a to a second end portion 14b.

A cylindrical pump stator 73 is provided on the inner peripheral surface of the housing 4 . The inner peripheral surface of the pump stator 73 radially faces the outer peripheral surface of the cylindrical portion 14 with a small gap therebetween. A thread groove (not shown) is formed on the inner peripheral surface of the pump stator 73 . Thus, the pump portion 3 includes a second pump structure 3 b configured by the cylindrical portion 14 of the rotating body 10 and the pump stator 73 of the housing 4 . A thread groove (not shown) may be formed on either the outer peripheral surface of the cylindrical portion 14 or the inner peripheral surface of the pump stator 73 .

(Structure of rotation mechanism)
In the example of FIG. 1 , the rotation mechanism 20 is composed of two units, a magnetic bearing unit 21 and a magnetic bearing integrated motor 22 .

The magnetic bearing unit 21 is provided around the rotating shaft 11 between the rotating shaft 11 and the wing support portion 12 . The magnetic bearing integrated motor 22 is provided around the rotating shaft 11 at a position closer to the other end 11b of the rotating shaft 11 than the magnetic bearing unit 21 is.

As shown in FIG. 4, the magnetic bearing unit 21 includes a magnetic bearing stator 21a and a magnetic bearing rotor 21b. The magnetic bearing stator 21 a is provided with a first coil 41 forming a first radial magnetic bearing 40 and a thrust coil 61 forming a thrust magnetic bearing 60 . The magnetic bearing rotor 21b is constructed by laminating a plurality of electromagnetic steel sheets in the axial direction.

<Magnetic bearing integrated motor>
As shown in FIG. 5, the magnetic bearing integrated motor 22 (motor stator 22a) includes a motor coil 24 constituting the magnetic bearing integrated motor 22, a second radial It has a second coil 51 forming a magnetic bearing, and a stator core 25 to which the motor coil 24 and the second coil 51 are respectively attached.

In other words, in the magnetic bearing integrated motor 22 illustrated in FIG. 5, the second coil 51 of the second radial magnetic bearing is further assembled to the motor stator 22a configured by the motor coil 24 and the stator core 25. .

Stator core 25 includes a plurality of teeth 25a and stator yoke 25b. A stator yoke 25 b is formed in an annular shape so as to surround the rotating shaft 11 . A plurality of teeth 25a radially extend toward the center of rotating shaft 11 from the inner peripheral surface of stator yoke 25b. A plurality of teeth 25a are arranged at equal angular intervals in the circumferential direction, and slots 25c for accommodating coils are formed between adjacent teeth 25a.

The motor coil 24 and the second coil 51 are wound around the respective teeth 25a. In FIG. 5 , the motor coil 24 and the second coil 51 are arranged radially in a plane perpendicular to the axial direction of the rotating shaft 11 . That is, both the motor coil 24 and the second coil 51 are arranged within the same slot 25c. In the example of FIG. 5, the motor coil 24 is arranged radially inward, and the second coil 51 is arranged radially outward.

The motor coil 24 and the second coil 51 are separate coils and electrically insulated. The motor coil 24 is electrically connected to the inverter 85c (see FIG. 3), and the second coil 51 is electrically connected to the inverter 85d (see FIG. 3). Inverter 85c supplies three-phase current (U-phase, V-phase, W-phase) to magnetic bearing integrated motor 22, for example. The magnetic bearing integrated motor 22 includes three sets of motor coils 24 (Mu, Mv, Mw) to which three-phase currents of U-phase, V-phase, and W-phase are respectively supplied. Inverter 85d supplies a three-phase current (U-phase, V-phase, W-phase) to magnetic bearing integrated motor 22, for example. The magnetic bearing integrated motor 22 includes three sets of second coils 51 (Su, Sv, Sw) to which three-phase currents of U-phase, V-phase, and W-phase are respectively supplied.

Further, the motor rotor 22b is provided on the rotating shaft 11 so as to rotate together with the rotating shaft 11. As shown in FIG. That is, the rotating shaft 11 is provided with a permanent magnet 26 at a position facing the stator core 25 in the radial direction with a gap therebetween (at the same position in the axial direction). In the example of FIG. 5, a permanent magnet 26 magnetized to the north pole is provided over half of the rotating shaft 11 in the circumferential direction, and is magnetized to the south pole over the other half of the rotating shaft 11 in the circumferential direction. A permanent magnet 26 is provided.

Although FIG. 5 shows an example of a 2-pole, 6-slot structure, the number of poles and the number of slots are not particularly limited. Further, in FIG. 5, the winding methods of the motor coil 24 and the second coil 51 are not limited to concentrated winding, and other winding methods such as distributed winding may be used.

The control unit 81 (see FIG. 3) supplies a current to each motor coil 24 via the inverter 85c (see FIG. 3) to cause the magnetic flux of the motor coil 24 and the magnetic flux of the permanent magnet 26 to interact. That is, the magnetic bearing integrated motor 22 gives the magnetic poles of the permanent magnets 26 attractive and repulsive forces by the magnetic flux of the motor coils 24 . The control unit 81 switches the motor coil 24 to which current is supplied according to the rotational angular position of the rotating body 10 to generate rotating magnetic flux and rotate the rotating body 10 at a desired rotational speed. The rotation speed of rotating body 10 by magnetic bearing integrated motor 22 is, for example, 10,000 rpm or more and 100,000 rpm or less.

Further, the control unit 81 (see FIG. 3) supplies current to the second coil 51 via the inverter 85d (see FIG. 3), and interaction between the magnetic flux of the second coil 51 and the magnetic flux of the permanent magnet 26 causes The coarseness and density of the combined magnetic flux are formed in the gap between the rotary shaft 11 (motor rotor 22b) and the stator core 25 (motor stator 22a). As a result, the magnetic bearing-integrated motor 22 applies a supporting force to the rotating shaft 11 in the direction in which the magnetic flux of the second coil 51 and the magnetic flux of the permanent magnet 26 strengthen each other.

For example, in FIG. 5, the magnetic flux of the two second coils 51 (Su) and the magnetic flux of the permanent magnet 26 strengthen each other in the gap on the N pole side of the motor rotor 22b and weaken each other in the gap on the S pole side. Therefore, a supporting force acts toward the N pole side (right side in the figure) where the amount of magnetic flux is large. FIG. 5 illustrates the U-phase second coil 51 (Su). of bearing force can be generated. The control unit 81 controls the current supply to each of the second coils 51 based on the sensor signals of the displacement sensors 7c and 7d and the rotation sensor 8 (see FIG. 3) so that the rotating body 10 is radially non-contact. The supporting force of the magnetic bearing integrated motor 22 is controlled so as to maintain the state.

Here, referring to FIG. 4 again, the operation of attaching the magnetic bearing unit 21 and the magnetic bearing integrated motor 22 to the rotating shaft 11 will be described. When attaching the magnetic bearing unit 21 and the magnetic bearing integrated motor 22 to the rotating shaft 11, a spacer member 29 is provided so as to sandwich the magnetic bearing unit 21 and the magnetic bearing integrated motor 22, respectively. Specifically, when attaching the magnetic bearing unit 21 and the magnetic bearing integrated motor 22 to the rotating shaft 11, the first spacer member 29a, the magnetic bearing unit 21, the second spacer member 29b, the magnetic bearing integrated motor 22, the second The 3-spacer member 29c is fitted to the rotating shaft 11 in this order. After the magnetic bearing unit 21, the magnetic bearing integrated motor 22, and the respective spacer members 29 are fitted onto the rotating shaft 11, pressure is applied to the ring 23 in the Z2 direction, whereby the rotating mechanism 20 rotates on the rotating shaft 11. can be attached to That is, the support member 27 is sandwiched together with the spacer member 29 in a state in which a compressive load is applied to the end portion of the one end 11a of the rotating shaft 11 and the ring 23 in the axial direction. Also, the spacer member 29 is provided as a positioning member for the rotation mechanism 20 .

As shown in FIG. 6, the motor rotor 22b includes permanent magnets 26, a support member 27, and a protective ring 28. As shown in FIG. The support member 27 is provided on the outer circumference of the rotating shaft 11 . Permanent magnet 26 is provided so as to surround the outer periphery of support member 27 . The protective ring 28 is provided on the outer periphery of the permanent magnet 26 so as not to contact with the pair of spacer members 29 in the axial direction. In the example shown in FIG. 6, the permanent magnets 26 are provided on the support member 27 in direct contact with each other.

The support member 27 is provided to receive, via a pair of spacer members 29, pressure applied in the axial direction when the motor rotor 22b is attached to the rotating shaft 11 (at the time of assembly). The support member 27 has an annular shape. Also, the support member 27 is configured by a metal cylinder extending in the axial direction of the rotating shaft 11 . Specifically, the support member 27 is made of stainless steel.

The protection ring 28 is provided to prevent the permanent magnets 26 from scattering due to the centrifugal force generated when the motor rotor 22b is rotated. The protection ring 28 has an annular shape. Here, the magnetic bearing integrated motor 22 has a function of a motor and a function of a magnetic bearing. A magnetic bearing generates a magnetic field in a predetermined direction for applying a bearing force in a predetermined direction. Therefore, when the motor rotor 22b rotates, an eddy current may occur. Eddy currents lead to excessive power consumption, loss of power to drive the motor and to generate the supporting force for the magnetic support.

Therefore, in this embodiment, the protection ring 28 is made of a non-conductive material. The non-conductive material that makes up the guard ring 28 has a lower electrical conductivity than the metal that makes up the support member 27 . Specifically, the protection ring 28 is made of non-conductive resin. More specifically, the protective ring 28 is made of fiber-reinforced plastic. The protection ring 28 is made of, for example, CFRP (Carbon Fiber Reinforced Plastics). CFRP has high strength in the direction in which the carbon fibers inside extend, and low strength in the direction in which the carbon fibers are arranged. Therefore, the protective ring 28 is provided on the permanent magnet 26 so that the carbon fibers inside the CFRP extend along the direction of rotation about the axial direction of the rotating shaft 11 . Thereby, it is possible to suppress scattering of the permanent magnets 26 due to the centrifugal force generated by the rotation of the rotating shaft 11 .

In this embodiment, the permanent magnet 26 is fitted into the support member 27 and fixed with an adhesive or the like. A protective ring 28 is fitted into the permanent magnet 26 fitted in the support member 27 and fixed with an adhesive or the like. A supporting member 27 to which the permanent magnet 26 and the protective ring 28 are fixed is fitted onto the rotating shaft 11 .

<Motor rotor>
A pair of spacer members 29 (a second spacer member 29b and a third spacer member 29c) shown in FIG. 7 are arranged so as to sandwich the support member 27 in the axial direction. In this embodiment, the motor rotor 22b is attached to the rotary shaft 11 by applying pressure in the Z2 direction to the support member 27 via the spacer member 29 (third spacer member 29c). The magnetic bearing integrated motor 22 is a motor for high-speed rotation. Therefore, a large pressure is applied when the motor rotor 22b is attached to the rotary shaft 11 so that the position of the motor rotor 22b and the like in the axial direction does not fluctuate during high-speed rotation. Therefore, the mechanical strength of the supporting member 27 in the axial direction of the rotating shaft 11 must be large. Specifically, the mechanical strength of the support member 27 in the axial direction of the rotating shaft 11 must be greater than the mechanical strength of the protective ring 28 in the axial direction.

As shown in FIG. 7, the permanent magnet 26 has a length 91 in the axial direction. The guard ring 28 also has a length 92 in the axial direction. The support member 27 also has a length 93 in the axial direction. The axial length 93 of the support member 27 is greater than the axial length 92 of the protective ring 28 . The length 93 and the length 92 are examples of the "first length" and the "second length" in the claims, respectively.

In addition, the protection ring 28 is positioned such that one end 28a of the protection ring 28 in the axial direction is between the one end 26a of the permanent magnet 26 and the one end 27a of the support member 27. are placed in The other end 28b of the protective ring 28 in the axial direction is located between the other end 26b of the permanent magnet 26 and the other end 27b of the support member 27. are placed in That is, in this embodiment, the axial length 92 of the protective ring 28 is greater than the length 91 of the permanent magnet 26 and smaller than the length 93 of the support member 27 .

In addition, in the present embodiment, the support member 27 is in contact with the pair of spacer members 29 at both end faces (the end face 27c and the end face 27d) in the axial direction. Specifically, the end surface 27 c of the support member 27 is in contact with the end surface 29 d of the spacer member 29 . Further, the end face 27d of the support member 27 is in contact with the end face 29e of the spacer member 29. As shown in FIG. That is, the support member 27 is sandwiched between the pair of spacer members 29 from both sides in the axial direction, and is fixed in a state in which a compressive load is applied in the axial direction. In the example shown in FIG. 7, the contact surfaces between the end faces (end face 29d and end face 29e) of the spacer member 29 and the axial end faces (end face 27c and end face 27d) of the support member 27 are flat. is an example of

In addition, in the present embodiment, at least one end surface (end surface 28 c or end surface 28 d ) of the protection ring 28 in the axial direction is out of contact with at least one of the pair of spacer members 29 . In the example of FIG. 7, both end surfaces of the protective ring 28 (the end surface 28c of the protective ring 28 and the end surface 28d of the protective ring 28) are out of contact with the pair of spacer members 29, respectively. Therefore, the protective ring 28 is supported by the support member 27 via the permanent magnets 26 without receiving an axial compressive load from either of the pair of spacer members 29 .

Further, in the present embodiment, the protection ring 28 has the outer surface 28e of the protection ring 28 in the radial direction of the rotating shaft 11 at substantially the same position as the outer surfaces 29f of the pair of spacer members 29, or the outer surfaces 29f of the pair of spacer members 29. It is configured to be positioned inside the outer surface 29 f of the spacer member 29 . The example of FIG. 7 is an example in which the position of the outer surface 28e of the protection ring 28 in the radial direction of the rotating shaft 11 is substantially the same as the outer surfaces 29f of the pair of spacer members 29. FIG. Specifically, the protection ring 28 and the spacer member 29 are separated by a distance 94 from the rotation center 11 d of the rotation shaft 11 to the outer surface 29 f of the spacer member 29 and a distance 94 from the rotation center 11 d of the rotation shaft 11 to the outer surface 28 e of the protection ring 28 . and the distance 95 to are approximately equal to each other.

[Effect of this embodiment]
The following effects can be obtained in this embodiment.

In this embodiment, by configuring as described above, it is possible to suppress damage to the protective ring 28 during assembly. In addition, loss due to eddy currents occurring in the protective ring 28 can be reduced. As a result, damage to the protection ring 28 during assembly can be suppressed, and loss due to eddy currents occurring in the protection ring 28 can be reduced.

Further, in the present embodiment, as described above, the axial length 93 of the support member 27 is greater than the axial length 92 of the protective ring 28 . Thereby, the pressure applied during assembly can be applied only to the support member 27 . As a result, it is possible to prevent the protection ring 28 from being damaged during assembly.

In addition, in the present embodiment, as described above, the protective ring 28 is configured so that the end 28a on one side in the axial direction of the protective ring 28 is connected to the end 26a on one side of the permanent magnet 26 and one side of the support member 27. and the other end 28b of the protective ring 28 in the axial direction is positioned between the other end 27a of the permanent magnet 26 and the other end 26b of the support member 27. 27b. This prevents both ends (ends 26a and 26b) of the permanent magnet 26 from protruding from both ends (ends 28a and 28b) of the protective ring 28 in the axial direction of the motor rotor 22b. can be done. As a result, when the motor rotor 22b rotates, it is possible to suppress scattering of the permanent magnets 26 due to centrifugal force.

In addition, in the present embodiment, as described above, the pair of spacer members 29 are arranged so as to sandwich the support member 27, and the support member 27 has both end surfaces (end surface 27c and end surface 27d) in the axial direction. Each is in contact with a pair of spacer members 29 , and at least one end face (end face 28 c or end face 28 d ) of the protection ring 28 in the axial direction is out of contact with at least one of the pair of spacer members 29 . Accordingly, when assembling by applying pressure to the support member 27 via the spacer member 29, the pressure from the spacer member 29 can be applied only to the support member 27, not to the protective ring 28. FIG. As a result, it is possible to further suppress the pressure applied during assembly from being applied to the protective ring 28 , so that damage to the protective ring 28 can be further suppressed.

Further, in the present embodiment, as described above, the outer surface 28e of the protective ring 28 in the radial direction of the rotating shaft 11 is positioned substantially at the same position as the outer surfaces 29f of the pair of spacer members 29. Alternatively, it is configured to be positioned inside the outer surfaces 29 f of the pair of spacer members 29 . Accordingly, it is possible to prevent the motor rotor 22 b from projecting further than the spacer member 29 in the radial direction of the rotating shaft 11 . Therefore, even when the motor rotor 22 b and the spacer member 29 are attached to the rotating shaft 11 , the amount of protrusion of the rotating shaft 11 in the radial direction can be made the same as the amount of protrusion of the spacer member 29 . As a result, when the motor stator 22a, the magnetic bearing unit 21, and the like are attached, the size of the gap with respect to the rotating shaft 11 becomes substantially constant, so that the rotating shaft 11 can be rotated stably.

Further, in the present embodiment, as described above, the support member 27 has an annular shape. Accordingly, it is possible to suppress an increase in the number of parts compared to a configuration in which the support member 27 is formed by combining a plurality of members, for example.

Moreover, in the present embodiment, as described above, the protection ring 28 is made of non-conductive resin. As a result, it is possible to prevent the weight of the protection ring 28 from increasing, for example, compared to a configuration in which the protection ring is formed of ceramic or the like. As a result, it is possible to reduce the weight of the motor rotor 22b while suppressing the occurrence of eddy currents in the protective ring 28. FIG.

Moreover, in this embodiment, as described above, the protection ring 28 is made of fiber-reinforced plastic. As a result, the mechanical strength of the protective ring 28 can be increased, for example, as compared with the case where the protective ring 28 is made of resin that does not contain fibers. As a result, it is possible to reduce the weight of the protective ring 28 and prevent the permanent magnets 26 from scattering.

Further, in the present embodiment, as described above, the magnetic bearing integrated motor 22 includes the motor rotor 22b including the rotating shaft 11 having an axial direction, the rotational force that rotationally drives the motor rotor 22b, and the motor rotor 22b that is magnetically supported. The motor rotor 22b includes a pair of spacer members 29 and a motor rotor 22b provided on the outer periphery of the rotating shaft 11, and the pressure applied in the axial direction during assembly is applied between the pair of spacer members 29. a support member 27 for receiving via the support member 27, a permanent magnet 26 provided so as to surround the outer periphery of the support member 27, and a pair of spacer members 29 provided on the outer periphery of the permanent magnet 26 so as not to contact with the pair of spacer members 29 in the axial direction. and a protective ring 28 having an annular shape, and the mechanical strength of the support member 27 in the axial direction of the rotating shaft 11 is greater than the mechanical strength of the protective ring 28 in the axial direction. Thus, like the vacuum pump 100 in the above embodiment, it is possible to provide the magnetic bearing integrated motor 22 capable of reducing loss due to eddy currents occurring in the protective ring 28 .

[Modification]
It should be noted that the embodiments disclosed this time should be considered as examples and not restrictive in all respects. The scope of the present invention is indicated by the scope of the claims rather than the description of the above-described embodiments, and includes all modifications (modifications) within the meaning and scope equivalent to the scope of the claims.

(First modification)
For example, in the above-described embodiment, an example of a configuration in which the ends 28a and 28b of the protective ring 28 are out of contact with the spacer member 29 was shown, but the present invention is not limited to this. For example, if either end (end 28a or end 28b) of protective ring 28 is not in contact with spacer member 29, either end (end 28a or end 28b) is not in contact with spacer member 29. may be in contact with Specifically, as shown in FIG. 8, the protective ring 28 and the spacer member 29 may contact each other by contacting the end surface 28d of the protective ring 28 and the end surface 29e of the third spacer member 29c. . Also, although not shown, the end surface 28c of the protective ring 28 and the end surface 29d of the second spacer member 29b may be in contact with each other.

(Second modification)
Further, in the above-described embodiment, the outer surface 28e of the protective ring 28 and the outer surface 29f of the spacer member 29 are positioned substantially at the same position, but the present invention is not limited to this. For example, the outer surface 28 e of the protective ring 28 may be configured to be located inside the outer surfaces 29 f of the pair of spacer members 29 . Specifically, as shown in FIG. 9, the distance 95 from the rotation center 11d of the rotating shaft 11 to the outer surface 28e of the protective ring 28 is the distance from the rotation center 11d of the rotating shaft 11 to the outer surface 29f of the spacer member 29. It may be configured to be smaller than distance 94 .

(Third modification)
Further, in the above embodiment, an example of a configuration in which the axial length 92 of the protection ring 28 is shorter than the length 93 of the support member 27 is shown, but the present invention is not limited to this. For example, as shown in FIG. 10 , the axial length 92 of the protective ring 28 may be greater than the length 93 of the support member 27 . Specifically, as shown in FIG. 10, the distance 95 from the rotation center 11d of the rotating shaft 11 to the outer surface 28e of the protective ring 28 is the distance from the rotation center 11d of the rotating shaft 11 to the outer surface 29f of the spacer member 29. When configured to be greater than the distance 94 , the axial length 92 of the protective ring 28 may be configured to be greater than the length 93 of the support member 27 .

(Fourth modification)
Moreover, although the example of the structure in which the motor rotor 22b includes a pair of spacer members 29 was shown in the above embodiment, the present invention is not limited to this. For example, as shown in FIG. 11, the rotating shaft 11 has a rib portion 11e on the one end 11a side of the rotating shaft 11, and the end surface 27c of the support member 27 is arranged so as to abut on the end surface 11f of the rib portion 11e. may be configured. Moreover, even without the spacer member 29, both ends of the row of members fitted on the rotating shaft 11 are sandwiched so as to contact the end surface 11f of the rib portion 11e and the ring 23 in the axial direction, and the compressive load in the axial direction is applied to the entire body. It should be fixed in the state of being added to .

(Fifth modification)
Moreover, although the support member 27 showed the example of a structure which has a ring shape in the said embodiment, this invention is not limited to this. For example, as shown in FIG. 12, the support member 27 may be composed of a first support member 27e and a second support member 27f having arc shapes. Specifically, the supporting member 27 may be configured by arranging the first supporting member 27e and the second supporting member 27f on the outer circumference of the rotating shaft 11, and arranging the permanent magnet 26 and the protective ring 28 on the outer circumference. .

(Other modifications)
Further, in the above-described embodiment, an example in which the protection ring 28 is made of CFRP is shown, but the present invention is not limited to this. For example, the protective ring 28 may be made of fiber reinforced plastic such as GFRP (Glass Fiber Reinforced Plastics) or AFRP (Aramid Fiber Reinforced Plastics). The protective ring 28 may be made of a material other than fiber-reinforced plastic, such as ceramic, as long as it can prevent the permanent magnets 26 from scattering due to the centrifugal force generated by the rotation of the motor rotor 22b. However, when the protection ring 28 is made of ceramic or the like, the weight of the protection ring 28 is greater than when the protection ring 28 is made of fiber-reinforced plastic. Therefore, the protection ring 28 is made of fiber-reinforced plastic. preferably.

Moreover, in the above-described embodiment, an example of a configuration in which the magnetic bearing unit 21 is provided for the rotating shaft 11 was shown, but the present invention is not limited to this. For example, the configuration may be such that the magnetic bearing unit 21 is not provided. If the magnetic bearing unit 21 is not provided, a mechanical bearing may be provided instead of the magnetic bearing unit 21 .

Moreover, although the magnetic bearing unit 21 has shown the example of the structure containing the 1st radial magnetic bearing 40 and the thrust magnetic bearing 60 in the said embodiment, this invention is not limited to this. For example, the first radial magnetic bearing 40 and the thrust magnetic bearing 60 may be provided separately.

Further, in the above-described embodiment, an example of a configuration in which the permanent magnets 26 are provided on the support member 27 in direct contact with each other has been described, but the present invention is not limited to this. For example, the permanent magnets 26 may be provided on the support member 27 in an indirect contact with an adhesive or the like.

[Aspect]
It will be appreciated by those skilled in the art that the exemplary embodiments described above are specific examples of the following aspects.

(Item 1)
a rotor including a rotating shaft having an axial direction;
a rotary blade provided on the rotary shaft;
a magnetic bearing integrated stator including a coil that applies a rotational force that rotationally drives the rotor and a bearing force that magnetically supports the rotor;
The rotor is
a pair of spacer members;
a support member provided on the outer periphery of the rotating shaft for receiving pressure applied in the axial direction during assembly via the pair of spacer members;
a permanent magnet provided to surround the outer periphery of the support member;
a non-conductive protective ring having an annular shape provided in non-contact with the pair of spacer members in the axial direction on the outer periphery of the permanent magnet;
The vacuum pump, wherein the mechanical strength of the rotating shaft of the support member in the axial direction is greater than the mechanical strength of the protection ring in the axial direction.

(Item 2)
A vacuum pump according to item 1, wherein the first axial length of the support member is greater than the second axial length of the protective ring.

(Item 3)
The protection ring is positioned such that one end of the protection ring in the axial direction is between one end of the permanent magnet and one end of the support member, and Item 2, wherein the other end of the protective ring in the axial direction is disposed between the other end of the permanent magnet and the other end of the support member. Vacuum pump as described.

(Item 4)
The pair of spacer members are arranged to sandwich the support member,
Both end faces in the axial direction of the support member are in contact with the pair of spacer members, respectively, and at least one end face of the protective ring in the axial direction is in contact with at least one of the pair of spacer members. A vacuum pump according to item 1, which is non-contact.

(Item 5)
In the protective ring, the position of the outer surface of the protective ring in the radial direction of the rotating shaft is substantially the same as the outer surface of the pair of spacer members, or the outer surface of the pair of spacer members is positioned inside. 5. The vacuum pump of item 4, wherein the vacuum pump is configured to be in the position of

(Item 6)
A vacuum pump according to item 1, wherein the support member has an annular shape.

(Item 7)
A vacuum pump according to item 1, wherein the protective ring is made of non-conductive resin.

(Item 8)
8. Vacuum pump according to item 7, wherein the protection ring is made of fiber-reinforced plastic.

(Item 9)
a rotor including a rotating shaft having an axial direction;
a magnetic bearing integrated stator including a coil that applies a rotational force that rotationally drives the rotor and a bearing force that magnetically supports the rotor;
The rotor is
a pair of spacer members;
a support member provided on the outer periphery of the rotating shaft for receiving pressure applied in the axial direction during assembly via the pair of spacer members;
a permanent magnet provided to surround the outer periphery of the support member;
a non-conductive protective ring having an annular shape provided in non-contact with the pair of spacer members in the axial direction on the outer circumference of the permanent magnet;
The magnetic bearing integrated motor, wherein the mechanical strength of the support member in the axial direction of the rotating shaft is greater than the mechanical strength of the protection ring in the axial direction.

(Item 10)
10. The magnetic bearing integrated motor according to item 9, wherein a first length of the support member in the axial direction is greater than a second length of the protection ring in the axial direction.

REFERENCE SIGNS LIST 11 rotating shaft 13 rotor blade 22 magnetic bearing integrated motor 22a motor stator (magnetic bearing integrated stator)
22b motor rotor (rotor)
24 motor coil (coil)
26 permanent magnet 26a end (end on one side of permanent magnet)
26b end (end on the other side of the permanent magnet)
27 support member 27a end (end on one side of support member)
27b end (end on the other side of the support member)
27c end face (end face on one side of support member)
27d end face (end face on the other side of the support member)
28 protection ring 28a end (end on one side of protection ring)
28b end (other end of protective ring)
28c end face (end face on one side of protective ring)
28d end face (end face on the other side of the protective ring)
29 pair of spacer members 29d end face (end face on one side of spacer member)
29e end face (end face on the other side of the spacer member)
51 second coil (coil)
92 length (second length)
93 length (first length)
100 vacuum pump

Claims (10)

a rotor including a rotating shaft having an axial direction;
a rotary blade provided on the rotary shaft;
a magnetic bearing integrated stator including a coil that applies a rotational force that rotationally drives the rotor and a bearing force that magnetically supports the rotor;
The rotor is
a pair of spacer members;
a support member provided on the outer periphery of the rotating shaft for receiving pressure applied in the axial direction during assembly via the pair of spacer members;
a permanent magnet provided to surround the outer periphery of the support member;
a non-conductive protective ring having an annular shape provided in non-contact with the pair of spacer members in the axial direction on the outer periphery of the permanent magnet;
The vacuum pump, wherein the mechanical strength of the rotating shaft of the support member in the axial direction is greater than the mechanical strength of the protection ring in the axial direction. 2. The vacuum pump of claim 1, wherein the first axial length of the support member is greater than the second axial length of the protective ring. The protection ring is positioned such that one end of the protection ring in the axial direction is between one end of the permanent magnet and one end of the support member, and 3. The other end of the protective ring in the axial direction is arranged at a position between the other end of the permanent magnet and the other end of the support member. The vacuum pump described in . The pair of spacer members are arranged to sandwich the support member,
Both end faces in the axial direction of the support member are in contact with the pair of spacer members, respectively, and at least one end face of the protective ring in the axial direction is in contact with at least one of the pair of spacer members. 2. The vacuum pump of claim 1, which is non-contact. In the protective ring, the position of the outer surface of the protective ring in the radial direction of the rotating shaft is substantially the same as the outer surface of the pair of spacer members, or the position is inner than the outer surfaces of the pair of spacer members. 5. The vacuum pump of claim 4, wherein the vacuum pump is configured to be in a position of 2. The vacuum pump of claim 1, wherein said support member has an annular shape. 2. The vacuum pump according to claim 1, wherein said protective ring is made of non-conductive resin. 8. The vacuum pump according to claim 7, wherein said protective ring is made of fiber reinforced plastic. a rotor including a rotating shaft having an axial direction;
a magnetic bearing integrated stator including a coil that applies a rotational force that rotationally drives the rotor and a bearing force that magnetically supports the rotor;
The rotor is
a pair of spacer members;
a support member provided on the outer periphery of the rotating shaft for receiving pressure applied in the axial direction during assembly via the pair of spacer members;
a permanent magnet provided to surround the outer periphery of the support member;
a non-conductive protective ring having an annular shape provided in non-contact with the pair of spacer members in the axial direction on the outer periphery of the permanent magnet;
The magnetic bearing integrated motor, wherein the mechanical strength of the rotating shaft of the support member in the axial direction is greater than the mechanical strength of the protection ring in the axial direction. 10. The magnetic bearing integrated motor according to claim 9, wherein a first length of said support member in said axial direction is greater than a second length of said protection ring in said axial direction.

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